Magnetic marking system, method and machine for producing the same

ABSTRACT

The invention relates to a marking system comprising wires exhibiting ultrasoft ferromagnetic properties. Said wires are arranged on or in a carrier and are associated with pre-established parallel positions which are separated by a constant gap according to a pre-established frame. The wires can be present or absent in each position, forming a detectable binary code. The inventive marking system can especially be embodied as a magnetically coded label. The invention also relates to a method for producing one such marking system by continuously incorporating ferromagnetic wires into an adhesive complex. The inventive marking system is used to identify and authenticate articles, products or objects.

This is a Divisional of U.S. patent application Ser. No. 10/510,920filed on Oct. 12, 2004, which is hereby incorporated by reference in itsentirety. This application claims priority to France Patent ApplicationNo. FR 02/04,607 filed Apr. 12, 2002, which is hereby incorporated byreference in its entirety.

The present invention relates in a general manner to the marking ofarticles, of products or of objects, with a view to their identificationand/or to their authentication. This invention pertains, moreparticularly, to a system for secure marking, by “magnetically codedlabel” or the like that can be “read” with the aid of an appropriatedetector. The marking system according to the invention possessesdiverse applications:

protection against the counterfeiting of industrial products, byauthentication of the original products;

traceability of products or of articles, via batches or product series,or possibly via an individual article;

identification of products or of articles, in commercial circles, as asupplement or possibly as a replacement for the traditional optical barcode.

The identification of articles and of products by optical bar code iscurrently well known, but it comprises drawbacks. In particular, anoptical bar code may easily be reproduced with the aid of a scanner or acommercial photocopier, or modified, so that it offers no genuinesecurity. Moreover, the necessarily visible nature of an optical barcode may give rise to drawbacks of an esthetic character, for certainkinds of objects or articles.

Systems for marking by magnetic labels have already been envisaged, evenif they are currently not very widespread. By way of examples, mentionmay be made here of the proposals contained in the documents FR 2344346,U.S. Pat. No. 4,964,951, U.S. Pat. No. 5,175,419 and U.S. Pat. No.5,729,201. These documents disclose:

use of wider or narrower parallel magnetized bands, that are thereforetoo easily visible (not transparent);

use of wires of variable length, combined with magnets, resulting in acomplex embodiment;

combination of wires having different magnetic characteristics;

simple association of magnetized wires, all equidistant, therebyprecluding any possibility of coding.

Most of the solutions already proposed therefore remain fairly complex,and hence expensive, by calling in particular upon complex and poorlycontrolled magnetic phenomena, without this resulting in improvedsecurity. In particular, for certain systems that utilize the length ofwires or bands having magnetic properties, an interruption to thesewires or bands may cause a modification of the response of the system.Furthermore, the known systems offer only a limited number ofcombinations for carrying out genuine coding, similar to a traditionalbar code, or else they achieve this only at the price of excessivecomplication, both at the level of the label itself and at the level ofthe detector to be used to “read” this label.

The present invention aims to remedy all of these drawbacks, byproviding a magnetic marking system which, while still beingparticularly simple and discreet, proves to be extremely reliable andallows coding with very many combinations.

For this purpose, the subject of the invention is essentially a magneticmarking system, which comprises, on or in a carrier, in correspondencewith pre-established parallel positions separated by a constant gapaccording to a pre-established frame, one or more wires having ultrasoftferromagnetic properties, these parallel wires being present or absentin each of said positions so as to form, through the set of wirespresent or absent, a detectable binary code.

In one embodiment of the invention, the carrier is of thetwo-dimensional type and constituted by a sheet of adhesive-coatedmaterial, which fixes the wires having ultrasoft ferromagneticproperties in their pre-established positions. This adhesive-coatedcarrier sheet is advantageously covered, at least in its initial state,with a protective sheet, of the silicone-coated paper kind, which thusalso covers the wires.

As a variant, the carrier is of the three-dimensional type, in whichcase the wires having ferromagnetic properties are embedded in thethickness of this carrier, at a small depth, by comparison with thedistance of two neighboring wires, so as in all cases to allow detectionby contact or by quasi-contact, with the aid of an electromagneticdetector moving over the surface.

The wires used for the production of such a marking are, preferably,glass-clad amorphous ferromagnetic filaments whose mode of production isexplained in “Ferromagnetic resonance in amorphous magnetic wires”, byS. A. BARANON et al., Phys. Met. Metall., No. 1, volume 67, pages 70 to75, 1989.

The metal core of such filaments possesses a diameter of the order ofsome ten to a few tens of microns, while the thickness of the glasscladding does not exceed a few microns so that the total diameter of thefilaments does not exceed 50 microns and that the filaments may beembedded in the adhesive mass of the carrier. The metal core of thesefilaments is made from an amorphous magnetic alloy essentially composedof cobalt or of iron, of nickel, of boron, of silicon and of carbon, invariable proportions that may be:

-   -   Fe or Co>40%,    -   0<Ni<20%,    -   18%<Si+B+C<35%

of other elements that may also be introduced with amounts of less than7%.

Such wires, by dint of their amorphous structure, may exhibit accordingto their composition a positive or negative coefficient ofmacnetostriction, and they possess a relatively weak magnetic field atsaturation (coercive field) (from 50 to 500 A/m), these properties beingvariable as a function of the composition of the alloy as well as of therelative proportions of alloy and of glass. A more precise descriptionregarding the magnetic properties of these wires may be found in:“Magnetic hysteresis in glass-covered and water-quenched amorphouswires” by H. CHIRIAC et al., Journal of Magnetism and Magnetic Materials177-181, pages 205 and 206, 1998.

As far as the detection device to be used to “read” the marking isconcerned, this is advantageously a portable device, consisting of anexcitation coil making it possible to create, in the space or immediatevicinity of the wire, an alternating magnetic field of greater strengththan the saturation field of the wire to be detected, and of twobalanced reception coils, mounted in opposition, in such a way as not todetect any response signal in the absence of a wire situated inproximity, inside the excitation volume zone. On the other hand, whenone of the ferromagnetic wires of a marking is close to the excitationcoil, said marking will undergo the influence of its magnetic field andits induced magnetization will describe a hysteresis cycle at the samefrequency as the excitation. The wire will then re-emit anelectromagnetic field of the same frequency which will be detectedessentially by that of the two reception coils that is situated closestto the wire, by virtue of an appropriate design of the detector. Byappropriate processing of the signal thus received on the detectiondevice, it is possible to determine the presence of a wire in proximityto the detection device. Consequently, by displacing this portabledetection device, in a direction transverse to the magnetic markingwires, it becomes possible to “read” instantaneously the binary codeborne by this marking.

Thus, the idea underlying the invention consists in the use offerromagnetic wires of identical nature, all possessing the sameultrasoft magnetic properties allowing their detection with the aid ofan electromagnetic excitation of proximity, and of low power (thisdetection being independent of the length of the wires), these wiresbeing positioned in a precise manner on or in a carrier, in the mannerof a bar code. The marking system thus constituted comprises, bycomparison with all the solutions previously proposed, a number ofimportant advantages:

-   -   The wires used being able to possess a very restricted diameter,        lying between ten and fifty microns, the system remains        invisible to the naked eye, and also imperceptible to the touch.        This makes it possible to place the wires on a transparent        carrier sheet, for example made of a transparent plastic, the        assembly being able to be placed on other normal labels while        remaining invisible.    -   The possibilities of coding are almost unlimited, given the very        large number of possible combinations of the number of wires and        of the relative positioning of these wires.    -   The principles of coding and of detection call neither upon a        differentiation of the magnetic properties of the wires, nor        upon a choice of their length, provided that this length is        greater than a minimum value, of the order of 5 millimeters. The        system therefore remains particularly simple, both as regards        the structure of the marking itself, and as regards detection.    -   All the parallel wires being identical (in diameter, length,        composition, magnetic properties, coercivity), one thus avoids        the risk of errors during the manipulation of the coils of        wires, for the production of the magnetic markings.    -   Insofar as the length of the wires exerts no influence, an        interruption of these wires (for example by a “cutter” blow)        would not be able to neutralize the system, which continues to        provide a well-identified response.    -   The ferromagnetic wires may be embedded in any molded or        fashioned material, or be included in a textile carrier, thereby        rendering the marking yet more discreet, and incorporable        directly into a product or object.    -   The flexibility of the wires, and as appropriate of their        carrier, permits any configuration of label, in particular to        form a magnetically coded label to be applied to a cylindrical        surface, such as the body of the bottle.    -   The magnetic properties utilized here of the wires are very        insensitive to variations in temperature, within a wide span        (from −50° C. to +80° C. for example), unlike LC type resonating        magnetic circuits screen-printed on magnetic labels that can be        interrogated at high frequency, in which the capacitance, hence        the resonant frequency, varies substantially with temperature,        given the thermal variation of the permittivity of the        dielectric used.    -   The wires being constituted from an ultrasoft amorphous magnetic        alloy, they possess weak coercivity which makes it possible to        call upon heads of proximity detectors of very weak radiated        field, hence having very low power consumption, thereby        increasing the autonomy of the portable detectors.    -   The detection of presence or of absence of the wires,        intervening as secondary antennas, is performed through an        analysis of the harmonics generated by these wires as they        approach magnetic saturation. Thus, the geometrical arrangement        of the parallel wires, and the coding that it permits, lend        themselves well to an analysis of the response by signal        processing, with implementation of processing software that can        tolerate a certain degree of error in the calibration of the        gaps between wires, thereby greatly facilitating the design of        the machines carrying out the laying of the wires.    -   Since the coding is based on wires having soft magnetic        properties, it cannot be destroyed, altered or erased by a stray        magnetic field, created deliberately or by chance, and of high        strength, in contradistinction to many existing magnetic coding        systems based on magnetically “hard” elements, such as bank        cards, magnetic stripe cards, or labels with two magnetic layers        (one hard and the other soft).    -   The small diameter of the wires precludes detection thereof by        antennas for electronic monitoring of articles (so-called EAS        antennas).    -   The response of each wire is independent of the strength of the        excitation field delivered by the detector (on condition that        the minimum strength value for saturating the wires is        achieved), and this response is therefore always the same,        thereby facilitating the adjustment of the field strength of the        excitation coil.    -   The principle of parallel wires allows easy production of the        magnetic markings in question, continuously or        semi-continuously, with sectioning to the desired length.

By way of example, the number of wires of the magnetically coded labelaccording to the invention lies between a minimum of one and a maximumof five. These wires may comprise, in addition to the wires defining abinary code, a first wire for tagging the start of the reading zone, inwhich the wires defining the binary code are positioned.

In the reading zone, the spacing between the possible positions of wiresis preferably equal at the minimum to 2 millimeters, such a minimum“pitch” being necessary to distinguish the wires during detection, whilepreventing several wires from being located simultaneously inside thezone of critical excitation strength, or preventing these wires fromhaving an influence on one another. The “pitch” is chosen as a functionof the dimensions of the labels and of the number of wires, this “pitch”possibly reaching several millimeters. The useful width of the labels(dimension transverse to the wires) may lie between a few millimetersand several centimeters, such a dimension permitting the use of a binarycode having several tens of bits, thus offering numerous combinations.

In the simplest design of the coding, the absence of any wire in a givenposition corresponds to the value ZERO, and the presence of a wire inthe relevant position corresponds to the value ONE.

A subject of the invention is also an industrial method for theproduction of the magnetic marking defined above, in the case where thismarking is constituted by a carrier sheet made of adhesive-coatedmaterial, which fixes the wires having ferromagnetic properties in theirpre-established positions, this carrier sheet having to be covered witha protective sheet.

This method consists, essentially, in unwinding a coil 3, of virginadhesive complex, which coil consists of a carrier sheet made ofadhesive-coated material and of a protective sheet initially coveringthe adhesive-coated face, in performing an operation of delamination ofthis adhesive complex, consisting in separating the adhesive-coatedcarrier sheet from the protective sheet, while advancing these twosheets, in depositing wires having ultrasoft ferromagnetic properties onthe adhesive-coated carrier sheet in the longitudinal direction oftravel of this sheet, while positioning the wires transversely in aprecise manner in correspondence with the code adopted for the marking,then in performing a relamination operation, consisting in returning theprotective sheet onto the adhesive-coated carrier sheet henceforthfurnished with the wires, and finally in rewinding the reconstitutedadhesive complex and incorporating the wires. One thus obtains a coil ofadhesive complex, incorporating the wires having ferromagneticproperties, distributed in the desired manner. The coil finally obtainedmay then be used as any other coil of adhesive complex that is intendedfor printing and cutting operations, to obtain separate adhesivecarriers which, in the present case, will for example be magneticallycoded labels with incorporated wires, or products fashioned in theformat of any sheets.

Finally, a subject of the invention is a machine specially intended forthe implementation of the method defined hereinabove, hence a machinefor the production of the magnetic marking, still in the case where thelatter is constituted by a carrier sheet made of adhesive-coatedmaterial, which fixes the wires having ferromagnetic properties in theirpre-established positions, this carrier sheet being covered with aprotective sheet.

The machine in question essentially comprises, in combination and fromupstream to downstream:

-   -   means for carrying and unwinding a coil of virgin adhesive        complex, consisting of a carrier sheet made of adhesive-coated        material and a protective sheet initially covering the        adhesive-coated face;    -   means of delamination, ensuring the separation of the        adhesive-coated carrier sheet and of the protective sheet;    -   means of bringing and depositing wires having ultrasoft        ferromagnetic properties onto the adhesive-coated sheet,        including means for the transverse positioning of these wires in        correspondence with the code adopted for the marking;    -   means of relamination, ensuring the rejoining of the protective        sheet and of the carrier sheet made of adhesive-coated material,        furnished with the wires; and    -   means of driving and winding up the reconstituted adhesive        complex incorporating the wires.

Advantageously, the means of bringing and depositing wires havingferromagnetic properties themselves comprise:

-   -   a vertically mobile carrier, for a plurality of coils of wire        having ferromagnetic properties;    -   means for the initial fastening and the pulling of the ends of        the wires emanating from these coils; and    -   between said coils of wire and these means of fastening and of        pulling, a device for transverse positioning of the wires.

Thus, the machine is equipped so as to initiate the process ofdepositing the wires, by fastening and pulling the ends of these wires,the carrier of the coils then being placed in the up position so as toavoid untimely gluing of the wires onto the adhesive-coated surface,especially during the transverse positioning of these wires to producethe desired code. Thereafter, the carrier of the coils is lowered, sothat the wires become tangential to the adhesive-coated material, andbegin to be fixed onto the latter. It will be noted that once fixed, thewires are driven forward with the carrier sheet, thereby renderingsuperfluous any specific means for unwinding the coils of wires or forpulling the wires.

Preferably, the machine is furthermore equipped, in its downstream part,with means for checking the presence and the correct positioning of thelaid wires, these means being able to intervene by “reading” the codeformed by the wires, doing so in a manner similar to the “reading” ofthe same code by a detection device.

In the simplest case, if these latter means note the abnormal absence ofa wire, generally caused by the “breakage” of this wire, the machinemust be stopped with a view to manual resetting.

However, in a refined embodiment of the machine, the latter alsocomprises, interposed between the abovementioned means of bringing anddepositing the wires and the means of relamination, at least oneadditional module for laying a wire, making it possible toautomatically, and in a quasi-instantaneous manner, cope with the“breakage” of a wire, noted by the means for checking the presence andthe correct positioning of the wires. Should the case arise whereseveral similar modules are thus interposed in succession, the machinecould even automatically cope with the “breakage” of two or more wires.Advantageously, this machine is also equipped with a marking device,making it possible to tag the defective zone, for the subsequentpractical use of the coil.

As may be easily understood, the method and the machine, defined above,allow the automatic continuous production, at high speed and in areliable manner, of coded “raw material” allowing printing and cuttingof an adhesive complex with a view to obtaining markings in accordancewith the invention, while making it possible to vary the codes of thesemarkings through the transverse positioning of the wires.

In any event, the invention will be better understood with the aid ofthe description which follows, with reference to the appendeddiagrammatic drawing which represents, by way of examples, variousembodiments and uses of this magnetic marking system, which alsoillustrates the method of production according to the invention, andwhich finally shows forms of execution of the machine for theimplementation of this method:

FIG. 1 is a front view of a magnetically coded label in accordance withthe invention;

FIG. 2 illustrates a use of this magnetically coded label;

FIG. 3 represents another marking in accordance with the invention,illustrating the use thereof;

FIG. 4 is a diagram illustrating the method of production ofmagnetically coded adhesive carriers according to the invention;

FIG. 5 is a side view of a machine for implementing this method;

FIG. 6 is a plan view from above of the machine of FIG. 5;

FIGS. 7, 8, 9 and 10 are partial diagrams of this machine, in side view,illustrating successive phases of its operation;

FIG. 11 is another partial diagram of the same machine, in plan viewfrom above;

FIG. 12 is a side view of a variant of this machine.

FIG. 1 shows a magnetic marking, made in the form of a magneticallycoded label 1. The latter comprises a carrier sheet 2 possessing anadhesive-coated face, and a protective sheet 3, of the silicone-coatedpaper kind, initially applied to the adhesive-coated face of the carriersheet 2.

Predefined on the magnetically coded label 1 are parallel positions 4,separated by a constant “pitch” or gap “e”. In certain of thesepre-established positions 4 are laid parallel wires 5 having ultrasoftferromagnetic properties. The absence or the presence of the wires 5, inthe various possible positions 4, defines a detectable binary code,specific to each label 1.

The marking also advantageously comprises, toward an end of the label 1,a first wire 6 having ferromagnetic properties, allowing the tagging ofthe start of the “reading zone” in which the other wires 5 arepositioned.

All the wires 5 and 6 are fixed, in their pre-established positions, bysimple adhesion to the adhesive-coated face of the carrier sheet 2. Theprotective sheet 3 initially covers these wires 5 and 6.

After removal of the protective sheet 3, the magnetically coded label 1can be fixed by gluing onto a product, an article or an object, such asa bottle 7 as illustrated in FIG. 2. The displacement of an appropriatedetector (not represented), along a direction F transverse to the wires5 and 6, makes it possible to “read” the binary code formed by thesewires.

In the exemplary use of FIG. 2, the flexibility of the magneticallycoded label 1 allows its winding around the body of the bottle 7. Ofcourse, as illustrated in FIG. 3, the magnetically coded label 1 orother marking according to the invention can also retain a planeconfiguration, in particular in correspondence with a plane face of anobject 8 to be identified or to be authenticated.

Still referring to FIG. 3, it will be noted that the marking 1 withwires 5, 6 having ferromagnetic properties may be embedded in a carrier2, itself incorporated with the object 8, the wires 5, 6 having,however, to be embedded at small depth, in such a way as to still allowtheir individual detection and the “reading” of the code formed by theset of these wires.

FIG. 4 illustrates the method of continuous production of a codedadhesive complex, serving as basis for the making of magnetically codedlabels such as that represented in FIG. 1.

The point of departure of the method is a coil 9 of virgin adhesivecomplex, consisting of a carrier sheet 2 possessing an adhesive-coatedface, and of a protective sheet 3 initially applied to theadhesive-coated face of the carrier sheet 2.

The coil 9 is unwound (arrow F1), and the adhesive complex whichconstitutes it is delaminated, that is to say the adhesive-coatedcarrier sheet 2 is separated from the protective sheet 3. The twosheets. 2 and 3 then advance along distinct paths (arrows F2 and F3)being suitably guided.

Along the path of the adhesive-coated carrier sheet 2, which is situatedbelow the path of the protective sheet 3, is carried out the laying ofthe wires 5 having ferromagnetic properties, emanating from respectivecoils of wire 10, the device for laying these wires 5 being symbolizedat 11. The wires 5 are thus laid parallel to one another, in thelongitudinal direction of travel F2 of the carrier sheet 2, and with avery precise transverse positioning, corresponding to the code adoptedfor the marking to be produced.

Thereafter, relamination is carried out, that is to say the protectivesheet 3 is returned to the carrier sheet 2, henceforth furnished withwires 5. The rejoining of two sheets 2 and 3 “imprisons” the wires 5between these two sheets 2 and 3, and one thus obtains a reconstitutedadhesive complex incorporating the wires 5.

Finally, the reconstituted adhesive complex is rewound, as indicated bythe arrow F4, to form a new coil 12. This latter may subsequently bere-employed, for the printing of the complex and for its separation intoindividual markings, such as the label shown in FIG. 1.

FIG. 5 et seq. represent, in greater detail, an automatic machineimplementing the method shown diagrammatically in FIG. 4.

Referring more particularly to FIGS. 5 and 6, the machine comprises,above an elongate bed 13 and from upstream to downstream: a subassembly14 for unwinding and delamination, a module 15 for depositing the wires,and a subassembly 16 for relamination and rewinding.

The upstream subassembly 14 itself comprises a horizontal carrier shaft17, for a coil 9 of virgin adhesive complex, to be unwound in thedirection of the arrow F1. On leaving the coil 9, this adhesive complexseparates into the carrier sheet 2, directed horizontally, and theprotective sheet 3, directed firstly vertically. The protective sheet 3passes over a tension device 18, placed in the upper part of theupstream subassembly 14. This subassembly 14 also comprises pairs ofplates 19 and 20, used to facilitate the linking up of the sheets 2 and3 during a change of coil 9.

The downstream subassembly 16 comprises various rollers 27, 28 and 29with horizontal axes, which guide the two sheets 2 and 3 in such a wayas to join them. This downstream subassembly 16 also comprises ahorizontal carrier shaft 24, receiving a coil 12 on which thereconstituted and coded adhesive complex is rewound. The carrier shaft24 is coupled up to an electric motor 25, which is provided for drivingthis carrier shaft 24, hence the coil 12, in continuous rotation.Between the last two rollers 28 and 29, the downstream subassembly 16furthermore comprises a detector 26 detecting the presence and thecorrect positioning of the laid wires.

The module 15 for depositing the wires, which is interposed between theupstream subassembly 14 and the downstream subassembly 16, itselfcomprises:

-   -   rollers 21, 22 and 23 with horizontal axes, for guiding the        adhesive-coated carrier sheet 2;    -   a removable carrier 30, of the “cassette” kind, for the coils of        wire 10, the carrier 30 being mounted vertically movably (arrow        F5), by means of a ram;    -   a subassembly 31 for initial fastening and pulling of the wires        5; and    -   between the “cassette” 30 and the subassembly 31, above the        rollers 22 and 23, a device 32 for transverse positioning of the        wires 5.

The cassette 30 is borne by a carriage 33, itself movable in thetransverse direction.

The subassembly 31 comprises a ram 34, oriented longitudinally, whoseupstream directed rod bears members 35 for fastening the ends of thewires 5. This subassembly 31 is itself transversely displaceable, bymeans of another ram 36.

Finally, the device 32 comprises a comb 37, whose various teeth aretransversely displaceable. A ram 38 is provided for controlling theraising and the lowering of the comb 37.

FIGS. 7 to 10 illustrate the successive phases of operation of themachine, on startup of the latter, that is to say after the introductionof a new “cassette” 30:

-   -   First phase (FIG. 7):    -   The “cassette” 30 being in the up position, the ends of the        wires 5, emanating from the various coils 10, are fastened to        the members 35, brought close to the “cassette” 30 by the        outstroke of the rod of the ram 34. The comb 37 is thus        retracted upward.    -   Second phase (FIG. 8):    -   The ram 34 is pulled back, thus drawing forward the wires 5,        whose unwound portions are held above the carrier sheet 2, so as        to avoid being in contact with the adhesive surface. At this        juncture, the wires 5 remain equidistant.    -   Third phase (FIG. 9):    -   The comb 37 is lowered, by actuation of the ram 38. The teeth of        this comb 37 then interpose themselves between the wires 5 and        each tooth pushes a wire laterally, in such a way as to obtain        the desired positions of and gaps between all the wires 5.    -   Fourth phase (FIG. 10):    -   The “cassette” 30 is lowered, so that the wires 5, previously        positioned, come into contact with the adhesive-coated face of        the carrier sheet 2. The “cassette” 30 is then realigned with        the carrier sheet 2, by transverse displacement—see also FIG. 11        (arrow F6).    -   Fifth phase (not illustrated):    -   The ends of the wires 5, previously grasped by the members 35,        are cut by means of an automatic cutting device (not        represented).    -   Sixth phase:    -   The motor 25 is turned on, so as to rotate the carrier shaft 24,        hence to begin to rewind the coded adhesive complex on the coil        12 (arrow F4) The two sheets 2 and 3 are thus driven forward, in        a synchronized manner (arrows F2 and F3), the deposited wires 5        being driven along with the adhesive-coated carrier sheet 2,        thereby unwinding them from their respective coils 10.

In the course of this process, the detector 26 constantly checks thepresence and the correct positioning of the laid wires 5, and it can inparticular instruct the stopping of the machine should there be a“breakage” of a wire 5, or poor reading.

FIG. 12 shows a variant of the machine described above, thesubassemblies and elements corresponding to those already describedbeing designated therein by the tags.

In this variant, between the module 15 for depositing the wires 5 andthe downstream subassembly 16 for relamination and rewinding, there isfurthermore provided an interposed module 39, which is designedaccording to the same principle as the module 15 but devised for thelaying of a single wire 5, emanating from a single coil 40. Incombination with the detector 26, the additional module 39 makes itpossible, should the absence of a wire be noted, to lay a replacementwire 5 on the carrier sheet 2, in the exact position of the missingwire.

As goes without saying, the invention is not limited solely to the modesof execution described above, by way of examples; it embraces, on thecontrary, all embodiment and application variants, be they in particularthe number of wires, or the nature of their carrier, or else theconstructional details of the machines. Thus, it is possible toincorporate into the marking, according to the same method as the otherwires, at least one nondetectable wire, for example nonmagnetic,constituting a “decoy”. With the same idea in mind, by reference to thevariant of FIG. 12, the interposed additional modules may be multipliedin order to allow the replacement of two or more broken wires.

1. A magnetic marking system, characterized in that it comprises, on orin a carrier, in correspondence with pre-established parallel positionsseparated by a constant gap according to a pre-established frame, one ormore wires having ultrasoft ferromagnetic properties, these parallelwires being present or absent in each of said positions so as to form,through the set of wires present or absent, a detectable binary code. 2.A magnetic marking system, characterized in that the carrier is of thetwo-dimensional type and constituted by a sheet of adhesive-coatedmaterial, which fixes the wires having ultrasoft ferromagneticproperties in their pre-established positions.
 3. The magnetic markingsystem as claimed in claim 2, characterized in that the adhesive-coatedcarrier sheet is covered, at least in its initial state, with aprotective sheet, of the silicone-coated paper kind, which thus alsocovers the wires.
 4. The magnetic marking system as claimed in claim 2,characterized in that the carrier sheet is a transparent sheet.
 5. Themagnetic marking system as claimed in claim 1, characterized in that thecarrier is of the three-dimensional type, in which case the wires havingferromagnetic properties are embedded in the thickness of this carrier,in their pre-established positions.
 6. The magnetic marking system asclaimed in claim 1, characterized in that the wires are glass-cladamorphous ferromagnetic filaments.
 7. The magnetic marking system asclaimed in claim 6, characterized in that the metal core of thefilaments possesses a diameter of the order of some ten to a few tens ofmicrons, the thickness of the glass cladding not exceeding a fewmicrons, the total diameter of the filaments not exceeding 50 microns.8. The magnetic marking system as claimed in claim 6, characterized inthat the filaments are made from an amorphous magnetic alloy composed ofcobalt or of iron, of nickel, of boron, of silicon and of carbon.
 9. Themagnetic marking system as claimed in claim 1, characterized in that thewires comprise, in addition to the wires defining a binary code, a firstwire for tagging the start of the reading zone.
 10. The magnetic markingsystem as claimed in claim 1, characterized in that in the reading zone,the spacing between the possible positions of wires is equal at theminimum to 2 millimeters.
 11. The magnetic marking system as claimed inclaim 1, characterized in that at least one nondetectable wire, forexample a nonmagnetic wire, constituting a “decoy” is incorporated intothe marking.
 12. A method for the production of a magnetic marking, moreparticularly of a marking constituted by a carrier sheet made ofadhesive-coated material, which fixes the wires having ferromagneticproperties in their pre-established positions, this carrier sheet havingto be covered with a protective sheet, as claimed in claim 3,characterized in that it consists in unwinding a coil of virgin adhesivecomplex, which coil consists of a carrier sheet made of adhesive-coatedmaterial and of a protective sheet covering the adhesive-coated face, inperforming an operation of delamination of this adhesive complex,consisting in separating the adhesive-coated carrier sheet from theprotective sheet, while advancing these two sheets, in depositing wireshaving ultrasoft ferromagnetic properties on the adhesive-coated carriersheet in the longitudinal direction of travel of this sheet, whilepositioning the wires transversely in a precise manner in correspondencewith the code adopted for the marking, then in performing a relaminationoperation, consisting in returning the protective sheet onto theadhesive-coated carrier sheet henceforth furnished with the wires, andfinally in rewinding the reconstituted adhesive complex andincorporating the wires.
 13. The method as claimed in claim 12,characterized in that the coil finally obtained is subjected to printingand cutting operations, so as to obtain separate adhesive carriers, forexample magnetically coded labels with incorporated wires.
 14. A machineintended for the implementation of the method as claimed in claim 12,for the production of the magnetic marking constituted by a carriersheet made of adhesive-coated material which fixes the wires havingferromagnetic properties in their pre-established positions, thiscarrier sheet being covered with a protective sheet, characterized inthat it comprises, in combination and from upstream to downstream: meansfor carrying and unwinding a coil of virgin adhesive complex, consistingof a carrier sheet made of adhesive-coated material and a protectivesheet; means of bringing and depositing wires having ultrasoftferromagnetic properties onto the adhesive-coated sheet, including meansfor the transverse positioning of these wires in correspondence with thecode adopted for the marking; means of relamination, ensuring therejoining of the protective sheet and of the carrier sheet made ofadhesive-coated material, furnished with the wires; and means of drivingand winding up the reconstituted adhesive complex incorporating thewires.
 15. The machine as claimed in claim 14, characterized in that themeans of bringing and depositing wires having magnetic propertiescomprise: a vertically mobile carrier, for a plurality of coils of wireshaving ferromagnetic properties; means for the initial fastening and thepulling of the ends of the wires emanating from these coils; and betweensaid coils of wire and these means of fastening and of pulling, a devicefor transverse positioning of the wires.
 16. The machine as claimed inclaim 15, characterized in that the means for the initial fastening andthe pulling of the ends of the wires emanating from the coils comprise aram, oriented longitudinally, whose frontward directed rod bears membersfor fastening the ends of the wires.
 17. The machine as claimed in claim15, characterized in that the device for transverse positioning of thewires comprises a comb, whose various teeth are transverselydisplaceable, a ram being provided for controlling the raising and thelowering of the comb.
 18. The machine as claimed in claim 15,characterized in that it is furthermore equipped, in its downstreampart, with means for checking the presence and the correct positioningof the laid wires, these means being able to intervene by “reading” thecode formed by the wires.
 19. The machine as claimed in claim 18,characterized in that it comprises, interposed between the means ofbringing and depositing the wires and the means of relamination, atleast one additional module for laying a wire, making it possible toautomatically cope with the “breakage” of a wire, noted by the means forchecking the presence and the correct positioning of the wires.